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25 Uppsatser om Rotational symmetries - Sida 2 av 2

Kraftanalys och framtagning av mätanordning för vertikala vindkraftverket Lucias bärarmar

The project contains a force analysis of the vertical axis wind turbine Lucia's supporting arms and a measuring device to experimentally measure the forces is made. The forces between the supporting arms and the tower are calculated theoretically and then simulated by a computere. A measuring devise is then designed to measure the forces experimentally. The forces acting on the attachment between the supporting arms and the tower is primarily the centripetal force, gravitational force and the aerodynamic forces on the rotor wings. The maximum forces were theoretically calculated and is 13.38 kN along the x-axis, -0.25 kN along the y-axis and then 0.5 kN along the z-axis.

Konstruktion av säkerhetslagerför svänghjul

This thesis is the result of the investigation and solution of a mechanicalproblem regarding flywheel malfunctions. A flywheel is, in short, a devicethat relies on a rotating object?s moment of inertia to store energy overshort time spans. This project is part of the development of a fourthflywheel prototype at the division for electricity at Uppsala university,which uses magnetic levitation to keep a hollow cylinder rotating at veryhigh speeds inside a vacuum chamber. Should the magnets fail however, orsome other error occur that leads to an uncontrolled state of rotation, thecylinder needs to be stabilized mechanically by a device usually referredto as ?back-up bearing?.

Utvärdering av metoder och modeller för att simulera växlingskomfort i entreprenadfordon

Good comfort for the driver of a construction machine is crucial. Gearshift comfort is an important part of the total comfort. Volvo Construction Equipment Components has a simulation environment of the powertrain, SimPow, which is implemented in Matlab/Simulink. SimPow is mostly used for simulation of control strategies and performance. In order to be able to study gearshifting comfort, Volvo has an interest in developing new models for SimPow.

Mätningar av statiska och dynamiska egenskaper för bakaxel.

To design new and high tech products the engineers rely more and more on computer based simulations to investigate the properties and behavior for a component or system.To verify these computer based simulations the dynamic properties for the components of the drivetrain needs to be verified. Therefore measurements of the stiffness and vibrations for the rear axle has been performed. This report show how the measurements has been implemented and evaluated, along with some interesting results for the rear axles properties.The static stiffness for the drive shaft along with the axle-gear has been determined. It is found that the stiffness for the whole rear axle is near the stiffness for the drive shaft, which means that the drive shaft becomes the dominant component of the system and affects the rear axle stiffness the most. The measured stiffness of the driveshaft is close to its theoretical stiffness.The stiffness for solely the hypoid-gear have been calculated using the stiffness for the rear axle and driveshaft, and thus has a range for the stiffness of the hypoid gear been determined.The backlash for the whole rear axle and for some individual components has been determined, where the backlash between pinion and crown-wheel has negligible impact on the total backlash.Measurements of the crown-wheel and pinion movements have been conducted, where the direction of movement is consistent with the theoretical direction of the forces.The vibration measurements show that the vibrations are more severe at certain rotational speeds.

Analys av lageregenskaper utifrån mätningar i testrigg

Vertical hydropower units has a rotating mass of up to 1000 tons. For the generator and turbine to work well the rotating system is required to be centered in relation to the surrounding structure. This is achieved by means of radial bearings. The dynamic characteristics of these bearings have a strong impact on the overall rotational dynamics of the total system and thus influence the vibrations in the unit. At Vattenfall Research & Development in Älvkarleby ongoing research is taking place on how the bearing parameters should be represented in the rotor dynamic calculations.

Förrotation till omrörare

The primary function of a mixer is to keep a fluid in constant motion. All mixing applicationsrequire varying degrees of small-scale turbulence and bulk flow. The performance of asubmersible mixer is measured by the thrust that it produces, while the strength of the bulkflow is dependent on the total amount of installed thrust.In a mixer, the fluid quickly flows past the propeller, and as a result, the current is mainlyaxial. The fluid will also obtain a rotating velocity, or a swirl, though this is significantly lessthan that of the propeller. During the process, the total amount of energy increases in the formof static pressure and kinetic energy.

Effekter av funktionell träning och medicinbollkast för att optimera kinematic sequence och x-factor stretch i golfsvingen

The interest for functional strength training in golf has grown the last decade and scientists are always trying to find training stategies to improve the biomechanical aspects of the swing. Kinematic sequence contains a proximal-to-distal sequence order towards impact, and an effective kinematic sequence in the down swing begins with a rotation in the pelvis and follows by an activation in thorax, arms and club in the respective order. The rotational torques in the proximal segments wanders through the body and to the more distal segments to create an effective energy ? and power transfer at impact. The x-factor stretch is the seperation between the rotation in the pelvis and the thorax at the top of the back swing and at the beginning of the down swing.

Minskande andelar kraftfoder i foderstaten under betesperioden : effekt på mjölkavkastning och betesbeteende hos mjölkkor

Feed costs constitute a large part of the expenses of dairy farmers. Pasture is a high quality feed with a low cost. However, feeding with concentrates has been shown to enhance milk yield (Leaver, 1985; Bargo et al., 2003; Stockdale, 2004). The purpose with this study was to investigate how milk yield and milk composition were affected as the concentrate proportion in the diet decreased. Pasture behaviour was examined to see if the different concentrate levels affected the time cows spent grazing and ruminating.

Lammproduktion på nio ekologiska gårdar i västra Sverige :

The purpose with this study was to analyze the possibilities to produce organic lambs and to hihglight the most common difficulties in such a production system. A description of current organic and conventional lamb production systems was conducted, both from Sweden and from some other countries. The Department of Animal Environment and Health at SLU in Skara performed the project together with The County Board of Agriculture in Västra Götaland and Värmland and The Swedish Animal Health Service. The project lasted from 2002 to 2004. The student report contains the years 2002 and 2003. In the year of 2003 there were 210 000 adult sheep in Sweden, of which 16 400 adult sheep were certified by KRAV. Of the different countries in Sweden, Västra Götaland and Gotland had the largest number of sheep, 14 and 13 per cent of the total number.

Utvärdering av strömaterial av restprodukter från wellpapp

SUMMARYFor thousands of years horses have been at people's side. They have been used for transportation at war, to save time, manpower and money. For practical reason, man has forced the horses into narrow spaces. Stabling includes factors as feeding and bedding. In the boxes the bedding materials must be kept clean and maintain good hygiene.

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